Note 1 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

March 31, 2020 (in thousands)	Level 1		Level 2		Level 3
Assets:
Investments:
Equity Funds – Held by Captive Insurance Company	$	1,130
Corporate Debt Securities – Held by Captive Insurance Company			$	2,842
Government-Backed and Government-Sponsored Enterprises’ Debt Securities – Held by Captive Insurance Company				5,379
Other Assets:
Money Market and Mutual Funds –Retirement Plans		2,526
Total Assets	$	3,656	$	8,221

December 31, 2019 (in thousands)	Level 1		Level 2		Level 3
Assets:
Investments:
Equity Funds – Held by Captive Insurance Company	$	1,586
Corporate Debt Securities – Held by Captive Insurance Company			$	2,124
Government-Backed and Government-Sponsored Enterprises’ Debt Securities – Held by Captive Insurance Company				6,060
Other Assets:
Money Market and Mutual Funds –Retirement Plans		2,363
Total Assets	$	3,949	$	8,184

Schedule of Inventory, Current [Table Text Block]

	March 31,		December 31,
(in thousands)	2020		2019
Finished Goods	$	29,996	$	31,863
Work in Process		15,811		16,508
Raw Material, Fuel and Supplies		52,345		49,480
Total Inventories	$	98,152	$	97,851

Schedule of Finite-Lived Intangible Assets [Table Text Block]

March 31, 2020 (in thousands)	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Remaining Amortization Periods (months)
Amortizable Intangible Assets:
Customer Relationships	$	22,491	$	11,543	$	10,948	85	-	185
Other		179		134		45	5	-	42
Total	$	22,670	$	11,677	$	10,993

December 31, 2019 (in thousands)	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Remaining Amortization Periods (months)
Amortizable Intangible Assets:
Customer Relationships	$	22,491	$	11,259	$	11,232	88	-	188
Other		179		121		58	8	-	45
Total	$	22,670	$	11,380	$	11,290

Finite-lived Intangible Assets Amortization Expense [Table Text Block]

	Three Months Ended
	March 31,
(in thousands)	2020		2019
Amortization Expense – Intangible Assets	$	296	$	296

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

(in thousands)	2020		2021		2022		2023		2024
Estimated Amortization Expense – Intangible Assets	$	1,140	$	1,105	$	1,105	$	1,104	$	1,099

Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]

	As of March 31,
(in thousands)	2020		2019
Noncash Investing Activities:
Transactions Related to Capital Additions not Settled in Cash	$	16,193	$	4,338

Accounts Receivable, Allowance for Credit Loss [Table Text Block]

	Three Months Ended
	March 31,
(in thousands)	2020			2019
Beginning Balance	$	1,339		$	1,407
Additions Charged to Expense (net of recoveries)		635			247
Reductions for Amounts Written Off		(293	)		(121	)
Ending Balance	$	1,681		$	1,533